How Do I Fix a Brocken Xbox 360 Disc?

i have an xbox game and when u put it into the xbox it loads and will bring you to the main menu and stuff but once i try to play the actual game or multiplayer it says it wont load. my xobx said that the game may be scratched or dirty so what should i do to fix it? i hear that toothpaste works, is that true? i dont want to try it until i know that it will work because i dont want to mess up the game any more so if u could help me out here that would be greatt

Suggestion:

http://www.youtube.com/watch?v=O2Qx-qsXulQ

Thats a video to show you how to use the toothpaste method.

I would just take the game to a game shop and pay a little to have it cleaned